fix(@schematics/angular): warn about loose matching in arrayWithExact… #2519

Job	Run time
list	26s
workflow (devkit-core-tests)	1m 17s
workflow (devkit-core-tests-rerun)	1m 18s
workflow (build-cli)	1m 43s
workflow (modules-builder-tests)	1m 44s
workflow (build-unit-tests)	2m 24s
	8m 52s

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